Liquid fuel burning apparatus



Jan. 4, 1938. F, 0, COLE 2,104,691

LIQUID FUEL BURNING APPARATUS Filed Dec. 26, 1935 ATTOR N EY Patented Jan. 4, 1938 PATENT oFFlcE LIQUID FUEL BURNING APPARATUS Frank o. cole, Dtroit,

Mich., assignor to The Timken-DetroitlAxle Company, Detroit, Mich.,

a corporation of Ohio Application December-.26, i935, serial No. 56,283

8Claims.

This invention relates to improvements in apparatus for combusting liquid fuel of the character which have come to be generally known as, the rotary wall flame typeof burner, and -it is more especially concerned with improvements in mixing devicescommonly called grilles for mixing the elements of combustion.

A requisite for the eflicient and complete combustion of fuel oils inV all rotary wall flame burners, and especially in those incorporating the Powers method of fuel and air distribution, as fullydescribed inthe copending application of Milton' A. Powers, Serial No. 729,928, filed June 9, 1934, in which large oil droplets are ung outwardly from a rcentral -distributing mechanism toward an impact wall, where they are broken upI into small, minute particles and mixed with a stream of air also directed outwardly from the central dls-. tributing mechanism, but in a separate layer, is that t'he impact wall must be maintained at ai suiliciently high temperature during normal operating conditions to completely vaporize the fueloil. Failure to maintain such a condition resuits in the unvaporized portion of the oil col-v lecting on the impact wall and ame ring and the igniters in the form of carbon deposits. These deposits, if allowed to grow, seriously hamper the eilicency of the burner and eventually cause failure. f

Fuel oils are classified as Nos. 1, 2, 3, 4, 5,. etc., the No. ,1 being the highest grade in the sense that it completely burns at a comparatively low temperature and costs the most. Hence the lowerthe grade of oil a burnerwill elciently burn," the greater is its commercial success. Burners for commercial, domestic use must be able to eiiiciently burn all grades of No. 2 oil and preferably No. 3 oil.

In burners not equlppedwith grilles, the flame, under ideal conditions, burns from the top edge of the impact wall; however, such ideal condi-` tions are not attainable in practice, due to variations in operating conditions, and hence to prevent the flame from burning below and on the in- 45 side of the impact wall, the burner is usually adjusted so that the flame will burn slightly above and to the rear of the impact wall. Such ames are usually very high and thin and their hottest point is relatively remote from the impact wall. 50 Since the intensity of heat derived at a given point by radiation, is inversely proportional to the square of the distance between the point and the source, it is evident that under these conditions the impact wall will not-absorb a great deal of 55 heat by radiation. It has been found, as a matter of fact,'that'the impact wall of even metal flame rings of such installations is only maintained at a temperature suiiicent to completely vaporize No. 1 fuel oils and in some instances, a very good grade of No. 2 oil.

The first grilles "applied to a domestic fuel oil burner were those illustratedv in theForrest A. Heath Patent No. 1,886,675, and although the efficiency of the burners towhch they were applied was materially increased, the limitations of such burners, by reason of the ceramic material from which they weremade and from'which also the flame ring was made, are generally known. Hence the present discussion is confined to metallic grilles such, for example, as illustrated in the copending John` A. Wilson application, Serial No. 682,374, filed July 27, 1933.

The Wilson metal grille, although primarily designed to make the flame shorter and bushier, incidentally increases the temperature of the ame ring by decreasing the distance. between the source of heat and theflame ring, thereby increasing the rate of heat radiation to the flame ring. Also, in this grille assembly some of the hot products of combustion are deected toward the back of the name ring and thus assist the `radiated heat. It has been found that with the Wilson 'metal grilles assembled in a burner of the character shown in Powers application Serial No. 729,928, the impact wall and ame ring are maintained at a temperature sufficient to completely vaporize the good grades of No. 2 oil; however, in some localities the specification oi-,No- 2 oil is not strictly adheredto, with the result that Avery poor grades of No. 2 oil arev attempted tobe burned and carbon deposition usually occurs.

My invention is designed as an improvement over the apparatus disclosed in the above-noted Wilson application, and a primary object is to provide grilles for an oil burner which will maintain the impact wall and the flame ring at a sufficiently high temperature to efiiciently burn Nos. 2 and 3 oils and good grades of No. 4 oils.

A further object is to provide a grille assembly fora rotarywall ameburner having a metal fiame ring, of such construction that it may be placed upon the ame ring in such manner that a maximum of radiated and convected heat will be absorbed thereby.

A further object is to provide a grille adapted to be placed in very close proximity to the upper edge of a fuel burner impact wall or flame ring, whereby the hottest portion of the flame is relatively close to the flame ring.

A further object is to provide grilles for a grille thegrille of myinvention; Y Figur `3 is aview of one of the grille supports ringadaptedtobeplacedontopofafuel burner impact wall or flamey ring and in relatively close proximity thereto. the grilles being adapted to be placed upon the ring intwo different positions, and designed to increase or decrease the operating temperature of the ilame ring, depending upon whichlposition the grilles are placed.

A further object is to provide a grille adapted to be positioned on the upper edge of a rotary wall ilamezburner impact ring and comprising a series of troughs and openings, and to equip it with supporting means whereby the grille may be positioned: on the impact ring in relatively close relation thereto and with the troughs either upright or inverted.

'A further object is to provide attaching means on a grillehaving a series of troughs and openings. of such nature that said grille may be attached to its supporting member with the troughs I of the grille in upright or inverted position.

'The above and further objects will more fully appear from'jthe following description and ap-l Y pended when considered in connection with the accompanying drawing wherein:

Figure 1 ,isl avertical sectional view taken substantially diametrically through a furnace or boilerin which is installed' a rotary wall flame -burner of the type herein contemplated and iu- .-corporating the grille assembly of my invention;

' Figure 2 is anenlarged view irl-perspective o of Figure 2 before bending;-

Figureiisanenlargedviewofthegrille o fmy invention mounted upon a flame ring with the troughs in upright pomtion; and Figure 5 is a view identical with Figure 4 with theexceptionthatthegrilleismountedininverted position. Y 4

Referring now to the drawing, wherein like reference characters refer to like parts wherever they occur throughout the several ilgures, and with particular reference to Figure 1, an oil burner generally indicated at A is centrally mounted in -a hearth B which closes the lower portion of the combustion chamber in a furnace or boiler C. The burner A comprises a 'motor I which drives a distributing head I and a fan 5. Oilis suppliedto the distributor head I froma suitable source through the inlet pipe 1 and is nung outwardly in streams by centrifugal force. due to rotation of distributing head I, through the iiinger. tubes l. Air is supplied to the fan blades II offanlthroughtheapertured aircollar il, the quantity thereof being controlled by the correspondingly apertured adjustable air gate it. '111e burner is substantially identical with that illustrated in the Alden and Powers Patent No. 1,882,694, and for more detailed information, reference may be had thereto. In this instance, howevcr,.the tubes are inclined and outwardly.- with theresult that the oil droplets take an upwardly curving-trajectory.

The fan I, as illustrated, is more fully explained and described in the copending application of John A. Wilson,.8erialv No. 22,246, iiled Hay 18, 1035. The lower portion of the burner 'A is surrounded by a shield. l'lwliich is for the purpose of preventing` overheating of the motor,

'anditisalsomorefllllydcrlbedinthe instmentioned Wilson application.

icorrefra'ctorymaterial Il whichissupportcd onampportingplateli. 'mesupportingnlste isinturnsupporteduponaringofangular section, which 1s rigidly secured to nie inner nu.

of furnace C. Plate 2| also supports the burner A and shield I1. Placed on top of hearth B and disposed inwardly of the periphery of the combustion chamber of furnace C is a flame ring assembly D, here illustrated as comprising a series of thin metallic segments placed end to end and connected together to define a continuous or endless ilame ring. YThese segments are more fully described in the copending application of Milton A. Powers, Serial No. 620,373, illcd July l, 1932, and sufilce it to say here that they comprise an air delecting surface 25, a groove or gutter I1 and an impact wall 29. However, if desirable, instead of the llame .ring assembly D, a pair of upright continuous metal strips having heights equal to the height of the impact wall 29 and the height of the point of juncture of the groove 21 and the defiecting surface 25 may be used, withoutdeparting from the spirit of my invention. This latter assembly is more fully disclosed in the copending application of Milton A. Powers, Serial No. 747,220, filed October 6, 1934. In either event the' disc-like blast of-air is deflected upwardly by the inner wall to the region of the impact wall impinged by the fuel..

A pair of igniters E are positioned substan diametrically opposite each other and in close proximity to'the ame ring D,and are provided with electrodes li which terminate in close proximity to the impact wall 2t of said iiame ring, thus providing a pair of'spark gaps. mectricai energy for producing the sparks is provided by the transformer F, the-circuit between the electrodes'being completed by the metallic flame ring.

Resting'on top ofthe impact wall Il of flame,

ring VD is a grille assembly G,.which compris a series of individualgrilies u (see Figure 2). Thefgrilles correspond to those disclosed in the above mentioned Wilson application and are preferablyV made of sheet metal having a high heatresistance and also high thermal conductivity and each of them. is formed from a fiat sheet of metal 'byecertain cutting and folding steps. Grilles Il comprise a rectangular box-like structure Il, the ends and sides of which are produced by bending the edges of the blank UP- wardly."1heboxisopen at the top andhas a sexies of lateral openings I1 extending from side to side of-the box. The openings are formed vby makinga'series of I-shaped cutsin thebase of the box and then foldingthe metal upwardly from the base and in this manner simultaneously Y' forming a series of transverse troughs Il.

Ateachendoftheboxtlaregrillesupports 4| which arealso preferably made of sheet metal having a high heat-resistance andthermai conductivity. Each support 4i is preferably, thoimh not necessarilyymade from a fiat sheet of metalv by'certain cutting and bending Operations. Figure 3 illustrates one of the supports after cutting but befor'e bending it into nnaiform. I nthe finished state supports 4| comprise a hat surface 43 havingasubstantiallyrectangularshapewith two adjacent corners thereof cut on as'at Il. to provide bearing faces.- and with separate inwardiybentilngers". Fingersl'larebentaiongthelr outerportions totake the slope of the bearing portions It. 'Ihe iiat surfaces I3 of supports Il are spot-welded substantially symmetrically to the ends of the box-like section Il of grilles 88 sothat the portions. ofthe mppcrts Il at each endoi the grilleareinalignment asareaiso theupperbentportionsofthengersl'l As seen`inli'is`ures4and5nngers4l are spacedfrcn of the air'and vapor.

bearing faces 45 a distance approximately equal to the thickness of the impact wall.

In assembling the grille von the impact wall oi the flame ring the upper bent portions of iingers l1 are positioned onA one side of said impact wall and the bearing faces 45 are placed on the other side. In this mannereach grille has a two-point support on the impact wall. 'I'he angle of bearing faces 45 is such that when the grille is in assembled position the plane of the upper or lower edge of the box section 35 is substantially normal to the path of air flow passing over the top of the 'impact wall, as seen in Figures 4 and 5.

Due to the fact that bearing faces I5 and ngers l1 are provided on both the upper and lower sides of each grille, the grilles may be assembled on a ame ring with the troughs 39 of-the grille in either upturned position as shown in Figure 4, or in downturned position as illustrated in Figure 5. The desirability of this optional mode of assembly will appear hereinafter.

It has been demonstrated in actual practice that if carbon deposition'occurs with the grilles in the position of Figure 4, i. e., with the troughs upturned, a reversal of the grilles to the position illustrated in Figure 5 will, in addition to eliminating carbon deposition, actually burn. off the carbon which had previously collected. With'my improved grille assembly this inverting Yis only necessary where very poor grades of fuel oil are encountered. y

There are several theories as to what takes place during normal operation of a burner in and aboutthe grille ring, but for the sake of clarity, I will confine my discussion toonly one of them. It is elementary that whenair is mixed with vaporized fuel oil, combustion will not take place, nor will it be supported until a certain critical mixture is obtained. If a given quantity of air is directed into a zone of vaporized oil at a relatively high velocity, combustion will not take place atthe point where the air meets .the vaporized oil, for there will be insuillcient mixing. The critical mixturewill occur at s'ome point removed from the point of contact and in the direction of the air iiow. Where there is no impedance presented to the ow ofthe mixed air and vapor the point of critical mixingv will occur ata point relatively remotev from the zone of vaporized fuel. `If a baille is placed in the line of the air and vapor iiow it will shorten the distance between the point at whichthe critical mixture is obtained and the Yinitial joinder is placed to the point ofjoinder the less the distance to the point of critical mixture will be.

In Figure 4 I have indicated the path of the oil droplets from the finger tubes 9 of the oil distributing mechanism by small circles and the path of the vaporized oil by small arrows. `I

have likewise indicated the path of the air flow from the air distributing vmechanism by means of dash lines. When the oil droplets strike the impact wall 29 they are immediately broken up into minute particles or vaporized (assuming thev apparatus has come up to operating temperature) and will be carried which is deflected by the deilecting portion of the flame ring segments. Themixture of air and oil vapor at the top of the impact wall 29 is not suiiicient to support combustion and if theY grille 33 were not present the point of critical mixture would be substantially aboverthe impact wall. However, with'the grille 33 assem- The closer this impedance .Y

upwardly by the air stream f bled in the position illustrated, o portion or the air and oil vapor mixture will strike the underside. of the troughs 39 and will be deilected, some of the deflected mixture passing upwardly through the openings 31, some bouncing back and causing eddies, someA passing over the ends and a good portion being directed toward the back of the flame ring. Thus, the grilles constitute mixing devices, and by using them the mixing of the air and oil vapor is speeded up and the point of critical mixture is obtained in a much shorter distance. In operation the grilles 33 get very hot,

becoming a dull cherry red and due to their closeness to the flame ring the radiant heat 'from them aids the deilected hot gases and mixture, in maintaining said flame ring at a comparatively high oil vaporing temperature. Also, since the ilame which burns from the top of the grilles is relativelyclose to tbeiiame ring it heats the zones in and around the ring and thus aids and abets this heating.

Referring now to Figure 5, substantially the same conditions and functions take place with the exception that, with the troughs 39 inverted, a greater quantity of air and oil vapor mixture and also hot gas of combustion are deflected towards the back of the llame ring. The grilles, accordingly, have a greater mixing power. This is accounted for by the confining action of' the sides and ends of the troughs, and the deflection of the mixture is confined within a smaller region. Thus faster mixing is obtained and although there is visibly. little or no `iiaine under have providedv novel mounting means for grilles' whereby they may be positioned relativelyA close to a flame ring and may be in either upright or inverted position. Moreovenif desired,supports Il may be made integral with the grilles.

Although I have illustrated supports Il as being secured to the grilles in symmetrical relationship, so that the grilles will assume av constant angularity with respect to the flame ring irrespective of whether they are supported'in' upright or inverted position, it is' to be understood that they may be asymmetrically mounted on bearing faces 45, and iingers 41 on one side: of the grille be givena different inclination so as to dispose the 'grilles at different angles. without departing from the spirit of the invention? The invention may be embodied in other specicV .forms without departing from the spirit or essential characteristics thereof. The present 'embodiment is therefore to be considered in all respects as illustrative and not'restrictive, the scope o'f the invention being indicated by the appended claims rather than the'foregoing description,

' and all changes which come within the meaning and range of equivalency of the claims are therefore lintended to beembraced therein.

In the appended claims the term carbureting member isintended to embrace the 'assembly of parts making up the carbureting ring irrespective ofwhether it be made of segments or continuous rings. 5

-Whatisclaimedanddesiredtobesecured'by United States Letters Patent is:

LInaliquidfuelburningdPDaratus-ofthe wallilame type, havingasubstantlally horizontal 5 hearthsim'oundedbyawalltobeheated,a`sub stantially endless carbureting member located above the hearth and adiacent'saidwall, said member having a fuel impact surface facing towardthecenterofthehearth,adistributorhcad 1o proiectinsupwardlythrouahsaidheartnoenter and spaced from said carburetingmember: said head having means for delivering a vdisc-like blastof airoutwardlyalongthehearthtoward said carbureting member, said-head further vcomprlsing means for projecting liquid fuel toward inunatomisedcondition from the head, said carbuneting member embodying a surface operable todeilectsaidblastofairinto proximity to said 4impact wall,l and an'inter- 2o mixingdevicemountedinapredeterminedposltion' on said carbureting member and operable to of considerable area and is'provided with aoplurality of open-sided pockets in'one of its sides. 3. In 'combination with a carhureting member having a comparatively thin..substantlal ly uvrisht impactwalLa generally flat grille assembly having a frame, saldframe having a supporting device at each end thereof operable to llt-over the upper'edg'e of said impact wall and rigidlysupportsaidgrillesssemblsneaehoisaid` supporting devices comprising a pair of fingerlihe elements projecting beyond the planes of said framein one direction, and adapted to straddle the upper edge of said impact wall, and a pair oi finger-like elements projecting beyond the planes of said frame in the opposite direction,wherebysaldgrille may'beremoved from said impact wall andsupported thereon in an 5o inverted position. l

4.The construction described in claim 3. wherelneachofsaldpslrsofilngerscomprisestwo flatmemberaoneilngerofeachpairbeing disposed substantiallynormal to said 'impact millA Ind the other being aimed substantially paralleltosaidimpactwallwhensaldsrilleisdis- `rinsed in perativepositiom'thcreupon.

-prising a ilat body 'membelnfa member secured to each end ofsfald'body memberandhavinganinclinedbesringface.saidsup porting member also having a filmer disposed substantiallynormsltotheplanethereofsnd ex- 1 tending in a direction substantially parallel to said bearing face, adapted to be mounted on said impact wall with said bearing facesndsaidflngersstraddling' thellpperolke thereo I 7. The device described .in claim 5, wherein said supporting members'l extendin both directions away from'said bo'dymcmber and thereby adaptsaidgrillesforsupportinsnllllrlahtoran inverted podtion upon said impact wall. l 8. In a liquid fuel burning apparatus of the wall llame type, having a substantially horisontal hearthsurroundedbyawalliobeheated,asub stantially endless carburetlng member located above the hearth andl adjacent said wall, said a member having 'a fuel impact surface facing toward the center of the hearth, a projecting upwardly through saidhearth center andspaced from said carbureting member; said head having means for deliver-ings disc-like blast l of air outwardly along the hearth toward said carbureting member. said head further comprising-means for projecting liquid fuel toward said impact wall in unatomiaedycondition from the head,saidcarhuretingmemberembodyingsmr 4| fa operable tooenee: nieblas: o: slr mm lproximity to said impact wall, and an intermixing device mounted in a predetermined position on' said carbm'eting member and operable to intimately intermix oil vapors and aircur- 4: rents rising above said carburcting member. said intermixing'fdevic'e having two substantially dat sides of appreciable area. one of which faces'the oncoming combustible mixtureand the other'l of which faces oppositely thereto, said device u Y havinga set of open-sided pockets provided thereon and facing the oncomingcombtible mixture. lor intimately intermising the components of thelatter.

-IR'ANKQOOIL u p CERTIFICATE OE CORRECTION. y Patent No. '2,1OL|Q,691 January )4, 1958.

' vEmxm'o. COLE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page h., second l column., line 21, claim?, for the claim referencel numeral "5". read 6; and

that the said LettersPatent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day .of February', A. D. 1958.

. Henry Vm Arsdale, (Seal) Acting Commissioner of Patents'. 

